The present invention relates to a process for the preparation of an alkylaniline having about 10 to 30 carbon atoms in the alkyl substituent which comprises reacting aniline with an olefin in the presence of a Friedel-Crafts catalyst.
It is known in the art that aromatic amines, such as aniline, may be alkylated with olefins in the presence of aluminum or aluminum-containing catalysts. In general, the olefins employed to alkylate the aromatic amine are lower molecular weight olefins, such as ethylene, propylene and butylene.
Thus, U.S. Pat. No. 3,275,690 discloses the alkylation of an aromatic amine, such as aniline, with a lower aliphatic olefin or cyclo-olefin in the presence of a Friedel-Crafts catalyst or a mixture of a Friedel-Crafts catalyst and aluminum or an alkali or alkaline earth metal. This patent teaches the use of lower aliphatic olefins having up to 5 carbon atoms and states that the olefins of interest are the normally gaseous olefins, such as ethylene, propylene, butylene-1, butylene-2 and isobutylene. This patent further teaches that cyclohexene is a suitable cyclo-olefin, but that olefins such as styrene are not contemplated for use in the process therein.
British Pat. No. 823,223 discloses a process for the production of alkylated aromatic amines by the reaction of an aromatic amine with an aliphatic olefin having up to 4 carbon atoms. The reaction is catalyzed by a number of aluminum-containing catalyst mixtures, such as a mixture of aluminum or an alloy of aluminum with a Friedel-Crafts catalyst.
U.S. Pat. No. 2,762,845 discloses a process for the production of nuclearly alkylated aromatic amines by the reaction of an aromatic amine with an olefin in the presence of aluminum. The aluminum can be added as metallic aluminum or as an aluminum alloy. Olefins which are described in this patent as suitable include ethylene, propylene, butylene, isobutylene, cyclohexene and styrene.
U.S. Pat. No. 2,814,646 discloses a process for the nuclear alkylation of a primary or secondary aromatic amine which comprises heating the amine with an olefin in the presence of an aluminum anilide catalyst. In this process, lower molecular weight olefins are preferred, such as ethylene, propylene and butylene.
U.S. Pat. No. 3,649,693 discloses a process for the selective orthoalkylation of aromatic amines which comprises heating an aromatic amine with an olefin in the presence of an aluminum anilide catalyst to form a reaction mixture containing orthoalkylated aromatic amines, and subsequently distilling the orthoalkylated aromatic amines from the reaction mixture without hydrolysis.
U.S. Pat. No. 3,923,892 discloses a process for the selective orthoalkylation of an aromatic amine which comprises reacting the aromatic amine with an olefin in the presence of an aluminum anilide catalyst, wherein the aluminum anilide catalyst is formed by adding an alkyl aluminum halide to the aromatic amine.